The present disclosure relates to the field of a transformer, in particular to a fixing structure for upper pressing blocks of a stereoscopic wound core open-ventilated dry-type transformer.
It is known to all that a stereoscopic wound core open-ventilated dry-type transformer is of non-packed structure; iron cores and coils are arranged in stereoscopic triangle; cushion blocks around are fixed directly by means of compression of a triangular frame. However, the compression method for the triangular area is especially important. Not only shall the strength of the compression force be considered so as to ensure short circuit resistance of the transformer, but also the way of compression shall be considered, so the insulation distance between the coils is not increased. At present, a relatively popular practice is that a screw is adopted in the center of the triangular area of transformer and the pressing blocks above are tensioned through lower clamp. This structure has the shortcomings that the tensioning screw is in the center of three coils so the insulation distance between the coils needs to be increased, and the insulating treatment of the tensioning screw has significant influence on the quality of the transformer. Therefore, the fixation of the pressing blocks in the triangular area of stereoscopic wound core open-ventilated transformer needs to be further optimized.
In order to solve the problems mentioned above, the present disclosure aims to provide a simple-constructed fixing structure which can fix pressing blocks in the triangular area of the transformer while the insulation distance between the coils would not be increased and ensure short circuit resistance of the transformer.
To solve the technical problems, the disclosure adopts the technical scheme:
A fixing structure for the upper pressing blocks of the stereoscopic wound core open-ventilated dry-type transformer includes three coils which are arranged vertically; three coils are arranged in triangle; an insulation ring is arranged at the upper end of each of the coils; one pressing block used for pressing the corresponding coil is placed on the upper surface of each insulation ring; an upper clamp is arranged above the pressing blocks; press rods for pressing the pressing blocks are arranged on the bottom surface of the upper clamp.
As an improvement of the technical scheme above, four pressing blocks are correspondingly arranged on each of the coils; four pressing blocks are uniformly distributed on the upper surface of the corresponding insulation ring and the included angle between any two adjacent pressing blocks is 90°.
As an improvement of the technical scheme above, each insulation ring is made of two semicircular insulation half-rings joining together. Each pressing block is pressed at the joint of the two semicircular insulation half-rings.
Preferably, the upper clamp is a hollow hexagonal framework; a pressing block fixing plate for pressing the pressing blocks below is arranged at the central position of the hexagonal framework; a transverse plate of the pressing block fixing plate arches upwards so the horizontal height of the transverse plate is higher than that of the upper end of an iron core of the corresponding coil; press rods for pressing the pressing blocks below are arranged on the lower surface of the transverse plate.
Furthermore, the length of each press rod arranged on the transverse plate is greater than that of each press rod arranged on the upper clamp.
The fixing structure has the beneficial effects that: according to the disclosure, the upper clamp presses the pressing blocks and then the pressing blocks press the coils so as to prevent the coils from loosening, thereby ensuring impact resistance of the coils; moreover, the pressing blocks which press the coils do not need to be tensioned by a lower clamp through utilizing a screw, and thus, the phase-to-phase distance between three coils will not be increased and the insulation distance between the coils is not to be increased; and in addition, four pressing blocks are evenly distributed on each coil, and thus the coils bear stress evenly, so the coils can be pressed better.